Optical element

ABSTRACT

To provide an optical element in which resistance of electrodes on a scanning side is reduced, a rate of effectively utilizing light generated at organic layers is promoted and shortcircuit between anodes and cathodes is prevented, there is provided an optical element including first electrodes formed on a substrate, organic layers at least including organic light emitting materials formed on the first electrodes and second electrodes formed on the organic layers, in which the first electrodes and the second electrodes are formed to be substantially orthogonal to each other and the organic layers are formed in an island-like shape at positions at which the first electrodes and the second electrodes intersect with each other.

This patent is a 37 C.F.R. 1.53(b) divisional of the parent applicationhaving the Ser. No. 09/365,905 filed Aug. 3, 1999, now U.S. Pat. No.6,215,250.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to an optical element including an organiclight emitting layer and an organic EL (electroluminescence) displayhaving organic electroluminescent elements.

2. Description of the Related Art

According to an organic EL display having a number of pixels eachconstituted by an organic electroluminescent element (hereinafter,referred to as organic EL element), voltage is applied to each of theorganic EL elements, electrons are injected from a cathode thereof andholes are injected from an anode thereof respectively to an organiclight emitting layer and light is emitted by causing recombination ofelectrons and holes in the organic light emitting layer.

As such an organic EL element provided to an organic EL display, forexample, there is a single hetero-structure type organic EL elementshown by FIG. 9. According to the organic EL element, an anode 2comprising a transparent conductive film made of ITO (Indium tin oxide)or the like is provided on a transparent substrate 1 of a glasssubstrate or the like, on which an organic layer 5 comprising a holetransport layer 3 and a light emitting layer 4 and a cathode 6 made ofaluminum or the like are provided in this order.

Further, according to the EL element constituted in this way, whenpositive voltage is applied to the anode 2 and negative voltage isapplied to the cathode 6, holes injected from the anode 2 reach thelight emitting layer 4 via the hole transport layer 3 and electronsinjected from the cathode 6 reach the light emitting layer 4,respectively and recombination of electrons and holes is caused in thelight emitting layer 4. At this occasion, light having a predeterminedwavelength is generated and is emitted from a side of the transparentsubstrate 1 to outside as shown by arrow marks in FIG. 9.

Accordingly, by arranging a number of the organic EL elements in, forexample, a matrix-like shape, an organic EL display is formed asmentioned above.

FIG. 10 shows an example of such a conventional organic EL display. Theorganic EL display shown by FIG. 10 is constituted such that a pluralityof transparent electrodes 8 in a stripe-like shape (band-like shape) areprovided on a transparent substrate 7, an organic layer 9 in asheet-like shape constituted by laminating a hole transport layer and alight emitting layer are provided on the transparent electrodes 8 and aplurality of cathodes 10 in a stripe-like shape (band-like shape) areprovided on the organic layer 9 to be orthogonal to the transparentelectrodes 8 and organic EL elements are formed at positions where thetransparent electrodes 8 and the cathodes 10 intersect with each other.

FIG. 11 is a view showing other example of a conventional organic ELdisplay. The organic EL display shown by FIG. 11 is constituted suchthat the transparent electrodes 8 in a stripe-like shape are provided asanodes on the transparent substrate 7, organic layers 11 a, 11 b and 11c in a stripe-like shape each comprising a hole transport layer and alight emitting layer are provided on the transparent electrodes 8 in astate in which the organic layers and the transparent electrodes 8 areorthogonal to each other and cathodes 12 in a stripe-like shape havingdimensions substantially equal to dimensions of the organic layers 11 a,(11 b and 11 c) are provided on the organic layers, 11 a, 11 d and 11 c.In this case, each of the organic layers 11 a, 11 b and 11 c is providedwith a light emitting characteristic in correspondence with one of red(R), green (G) and blue (B) by which the organic EL display constitutesa display of full color or multiple color.

An explanation will be given of image display by the color organic ELdisplay shown by FIG. 11. According to the color organic EL display, asshown by FIG. 12, a scanning circuit 13 is connected to the transparentelectrodes 8 and a brightness signal circuit 14 is connected to thecathodes 12. Further, the organic layers 11 a, 11 b and 11 crespectively emit light by time-sequentially applying signal voltages tothe organic layers 11 a, 11 b and 11 c at positions intersecting withthe transparent electrodes 8 and the cathodes 12 by the scanning circuit13 and the brightness signal circuit 14. Accordingly, the organic ELdisplay functions as an image reproducing apparatus by such a control.

However, there is the following inconvenience in the organic EL display.

In the case in which the organic EL display is driven by, for example,the simple matrix system, when a number of scanning lines is severalhundreds, in order to ensure sufficient brightness, current of about 1A/cm² need to flow. Then, in this case, although it differs dependingalso on the size of the display, current of about 0.5 through 1 A isflowed instantaneously in the transparent electrodes 8 connected to thescanning circuit 13.

Further, the resistance value of ITO which is normally used for thetransparent electrode 8 is about 100 times as much as that of a metal ofaluminum or the like and its alloy. Accordingly, when large current ofabout 0.5 through 1 A is flowed as mentioned above, voltage drop in thetransparent electrode 8 is increased. Further, when such a large voltagedrop is caused in the transparent electrode 8, voltage applied on therespective organic EL elements in the organic EL display becomesnonuniform and the display function of the organic EL display issignificantly deteriorated.

That is, when the organic EL display is driven by the simple matrixsystem, although depending also on the display size, current flowing inthe electrodes on the scanning side becomes 100 through 1000 times asmuch as current flowing in the electrodes on the brightness signal sidein view of the drive principle. However, in the case of the organic ELdisplay, large current is flowed in the transparent electrode 8 havinghigh resistance. Therefore, large voltage drop is caused in atransparent conductive film constituting the transparent electrode 8.Voltage applied on the organic layers 11 a, 11 b and 11 c constitutingthe respective pixels becomes nonuniform by which the display functionis deteriorated and power consumption in the transparent electrode 8 isincreased.

Further, in the case of the color organic EL display shown by FIG. 11,the organic layers 11 a, 11 b and 11 c are formed over an entire lowerface thereof along the length direction of the cathodes 12 formed in astripe-like shape. Owing to such a structure, brightness signalsnecessary for respective colors of R, G and B must be provided from thecathodes 12. Therefore, the brightness signal circuit 14 must beconnected to the cathodes 12 and the scanning circuit 13 must beconnected to the transparent electrodes 8.

Further, as mentioned above, power consumed in the transparentelectrodes 8 is increased and accordingly, low power consumptionformation in the entire organic EL display is deteriorated. Accordingly,to provide the organic EL display having low power consumption, theresistance of electrodes on the scanning side needs to reduce to therebyreduce voltage drop.

As a measure for reducing the resistance of the scanning sideelectrodes, there is disclosed a technology in which metal wirings areinstalled along with the transparent electrodes in JP-A-5-307997.According to the technology, a metal having low resistance is providedat a portion between the transparent electrode and the organic layer tothereby achieve low resistance formation of the scanning electrode.

However, in order to achieve sufficient low resistance formation by sucha technology, an area of the metal wiring provided along with thetransparent electrode needs to magnify as large as possible. When thearea of the metal wiring is magnified in such a manner, the metal wiringcovers the organic layers 11 a, 11 b and 11 c constituting lightemitting portions, as a result, the light emitting area of the organicEL element is reduced and the light emitting efficiency is deteriorated.

Further, although it is conceivable to achieve low resistance formationby enlarging the film thickness of metal, in such a case, there causes aconcern of bringing about shortcircuit between the anode and the cathodeand nonuniformity in the film thickness of the organic layer.

Further, according to the conventional organic EL display shown by FIG.10 and FIG. 11, the organic layer 9 (11) is formed over an entire faceor formed continuously along the length direction of the cathode 12. Theorganic layer 9 (11) is provided with light guiding performance andaccordingly, a portion of light generated in the organic layer 9 (11) ispropagated in the organic layer 9 (11) and is guided in the transversedirection relative to the transparent substrate 7 as shown by arrowmarks C in FIG. 13. Then, the portion of light is attenuated in theguiding operation and the remaining portion is lost by being emittedfrom peripheral pixels.

That is, it is preferable that all of light generated in the organiclayer 9 (11) is emitted to outside of the organic EL display bytransmitting through the transparent electrodes 8 and the transparentsubstrate 7 and utilized as display light. However, according to thestructure of the conventional organic EL display, a portion of lightgenerated in the organic layer 9 (11) is not utilized as display lightby which the efficiency of utilizing light is deteriorated and thebrightness is reduced.

Further, a portion of light transmitted through the organic layer 9 (11)and guided in the transverse direction relative to the transparentsubstrate 7, is emitted to outside of the transparent substrate 7 bybeing emitted from the organic layer 9 (11) constituting peripheralpixels by which light originally generated at the peripheral pixels isinterfered by the guided light and there also is a concern in whichcross talk is caused and color reproducing performance is deteriorated.

Therefore, according to the conventional organic EL display, it isdifficult to provide sufficient brightness and the color reproducingperformance and in order to provide excellent display function, it isnecessary to prevent light transmitting through the organic layer frombeing guided.

Further, according to the conventional organic EL display, the organiclayer 9 (11) at a surrounding of an end portion 8 a in the widthdirection of the transparent electrode 8 is electrically fragile andaccordingly, as shown by an arrow mark D in FIG. 13, shortcircuit iscaused between the anode (transparent electrode) and the cathode 10 (12)and pixels cannot be selected.

SUMMARY OF THE INVENTION

The present invention has been carried out in view of theabove-described situation and it is an object of the present inventionsto provide an optical element in which resistance of electrodes on ascanning side can be reduced, a rate of effectively utilizing lightgenerated at the organic layers is promoted and shortcircuit betweenanodes and cathodes is prevented and to provide an organic EL display inuse thereof.

According to a first aspect of the invention, there is provided anoptical element comprising first electrodes formed on a substrate,organic layers at least including organic light emitting materialsformed on the first electrodes and second electrodes formed on theorganic layers, wherein the first electrodes and the second electrodesare formed to be substantially orthogonal to each other and wherein theorganic layers are formed in an island-like shape at positions at whichthe first electrodes and the second electrodes intersect with eachother.

According to a second aspect of the invention, there is provided theoptical element according to the first aspect wherein the secondelectrodes are formed to cover upper faces and side faces of the organiclayers.

According to a third aspect of the invention, there is provided theoptical element according to the first aspect wherein a brightnesssignal circuit is connected to the first electrodes and a scanningcircuit is connected to the second electrodes.

According to a fourth aspect of the invention, there is provided anoptical element wherein first electrodes comprising a transparentconductive material are arranged on a substrate in a stripe-like shape,wherein organic layers including at least organic light emittingmaterials are formed above an insulating film having openings formed onthe first electrodes, wherein second electrodes are formed on theorganic layers to be substantially orthogonal to the first electrodesand wherein the organic layers are forme in an island-like shape atpositions at which the first electrodes and the second electrodesintersect with each other.

According to a fifth aspect of the invention, there is provided theoptical element according to the fourth aspect wherein the secondelectrodes are formed to cover upper faces and side faces of the organiclayers.

According to a sixth aspect of the invention, there is provided theoptical element according to the fourth aspect wherein the firstelectrodes are formed to extend in one direction, the second electrodesare formed to extend to other direction and when a width of the firstelectrodes in a direction orthogonal to the one direction is designatedby a notation w1, a width of the opening in a direction orthogonal tothe one direction is designated by a notation w2 and a width of theorganic layers in a direction orthogonal to the one direction isdesignated by a notation w3, the following relationship is established.

w1≧w3>w2.

According to a seventh aspect of the invention, there is provided theoptical element according to the fourth aspect wherein a brightnesssignal circuit is connected to the first electrodes and a scanningcircuit is connected to the second electrodes.

According to an eighth aspect of the invention, there is provided theoptical element according to the fourth aspect wherein the firstelectrodes comprise ITO (indium tin oxide) and the second electrodescomprise Al (aluminum).

According to a ninth aspect of the invention, the optical elementaccording to the fourth aspect further comprises third electrodesdisposed between the organic layers and the second electrodes andwherein the third electrodes are formed to cover upper faces and sidefaces of the organic layers.

According to a tenth aspect of the invention, there is provided theoptical element according to the fourth aspect wherein the insulatinglayer is made of polyimide.

According to an eleventh aspect of the invention, there is provided theoptical element according to the fourth aspect wherein the openings areformed in a rectangular shape.

According to a twelfth aspect of the invention, there is provided theoptical element according to the fourth aspect wherein the organiclayers include organic layers of red color, green color and blue color.

According to a thirteenth aspect of the invention, there is provided anoptical element wherein a plurality of first electrodes comprising atransparent conductive material are arranged on a transparent substratein a stripe-like shape, wherein organic layers including at leastorganic light emitting materials are formed on an insulating film havingopenings formed on the first electrodes, a plurality of secondelectrodes are formed on the organic layers to be substantiallyorthogonal to the first electrodes and wherein the organic layers areformed in an island-like shape only at positions at which the firstelectrodes and the second electrodes intersect with each other.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A and 1B are views showing an outline constitution of anembodiment of an optical element according to the invention in whichFIG. 1A is a plane view showing essential portions and FIG. 1B is asectional view taken along a line A—A of FIG. 1A;

FIGS. 2A, 2B, 2C, 2D, 2E and 2F are side sectional views showingessential portions for explaining a method of fabricating the opticalelement shown by FIG. 1 in an order of steps;

FIG. 3 is a connection diagram of a drive circuit in an example in whichthe optical element shown by FIG. 1 constitutes an organic EL display;

FIG. 4 is plane view showing a modified example of pixel arrangement inthe optical elements according to the invention;

FIG. 5 is a side sectional view showing essential portions forexplaining operation of the optical element shown by FIG. 1;

FIG. 6 is a plane view showing a modified example of an optical elementaccording to the invention;

FIG. 7 is a plane view showing a modified example of an optical elementaccording to the invention;

FIG. 8 is a plane view showing a modified example of an optical elementaccording to the invention;

FIG. 9 is a side sectional view showing an outline constitution of aconventional single hetero-structure type organic EL element;

FIG. 10 is a perspective view showing an outline constitution of anexample of a conventional organic EL display;

FIG. 11 is a perspective view showing an outline constitution of otherexample of a conventional organic EL display;

FIG. 12 is a perspective view showing a state of being connected with adrive circuit of the organic EL display shown by FIG. 11; and

FIG. 13 is a side sectional view showing essential portions forexplaining the problem of the conventional organic EL display.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A detailed explanation will be given of embodiments of the invention asfollows.

FIGS. 1A and 1B are views showing an outline constitution of anembodiment of an optical element according to the invention. In FIGS. 1Aand 1B, numeral 20 designates an optical element applied to an organicEL display and numeral 21 designates a transparent substrate made of alight transmitting material such as glass.

According to the optical element 20, on the transparent substrate 21, asshown by FIG. 1B, a plurality of first electrodes 22 in a stripe-likeshape comprising ITO are formed in parallel and an insulating layer 23made of polyimide is formed to cover the first electrodes 22. In theinsulating layer 23, right above the first electrodes 22, there areformed and arranged a number of openings 24 having a rectangular shapefor making surfaces of the first electrodes 22 face outer side in adot-like shape.

Further, on the first electrodes 22, there are installed organic layers25 a, 25 b and 25 c from insides of the openings 24 of the insulatinglayer 23 to the insulating layer 23. The organic layers 25 a, 25 b and25 c communicate with the first electrodes 22, that is, connected to thefirst electrodes 22 via the openings 24 and are formed in a rectangularshape larger than the openings 24 in plane view as shown by FIG. 1A.Further, all of the organic layers 25 a, 25 b and 25 c are formed in anisland-like shape independently from each other and are arranged withina width w1 of the first electrodes 22 in plane view. Further, theorganic layers 25 a, 25 b and 25 c are formed and arranged incorrespondence with respectives of the openings 24 and are installed ina state of respectively covering corresponding ones of the openings 24.

Therefore, a plane view shape of the openings 24 is formed in a sizesmaller than a plane view shape of the organic layers 25 a, 25 b and 25c. As shown by FIGS. 1A and 1B, a width w2 of the opening 24 in adirection orthogonal to a longitudinal direction of the first electrode22 is narrower than a width w3 of the organic layers 25 a, 25 b and 25c. Further, as mentioned above, the organic layers 25 a, and 25 b arearranged within the width w1 of the first electrodes 22 in plane viewand accordingly, a width w3 of the organic layers 25 a, 25 b and 25 c isequal to or smaller than the width w1 of the first electrodes 22.Accordingly, a relationship of w1≧w3>w2 is established among the widthw1 of the first electrodes 22, the width w2 of the openings 24 and thewidth w3 of the organic layers 25 a, 25 b and 25 c.

Further, from such a constitution, as shown by FIG. 1B, the organiclayers 25 a, 25 b and 25 c are not present directly above end portions22 a of the first electrodes 22 in the width direction and theinsulating layer 23 is interposed therebetween.

Further, the organic layers 25 a, 25 b and 25 c are respectivelyprovided with light emitting layers comprising organic light emittingmaterials in correspondence with respective colors of red (R), green (G)and blue (B), are further provided with hole transport layers, electrontransport layers, hole block layers and so on and are formed bylaminating them. Further, according to the embodiment, the lightemitting layer of the organic layer 25 a corresponds to red color (R),the light emitting layer of the organic layer 25 b corresponds to greencolor (G) and the light emitting layer of the organic layer 25 ccorresponds to blue color (B), respectively.

Further, above the transparent substrate 21, a plurality of secondelectrodes 26 in a stripe-like shape are formed in parallel and arearranged in a state of being substantially orthogonal to the firstelectrodes 22. The second electrodes 26 are of low resistance comprisinga metal or an alloy having light shielding performance and according tothe embodiment, the second electrodes 26 are made of aluminum. Further,the second electrodes 26 are formed to cover upper face sides of theorganic layers 25 a, 25 b and 25 c arranged on the first electrodes 22.Therefore, the organic layers 25 a, 25 b and 25 c are arranged to beindependent from each other respectively at positions where the firstelectrodes 22 and the second electrodes 26 intersect with each other.

In this case, according to the embodiment, as shown by FIG. 1B, thesecond electrodes 26 covering the upper face sides of the organic layers25 a, 25 b and 25 c are formed to cover not only the upper faces of theorganic layers 25 a, 25 b and 25 c but also side faces thereof exposedabove the insulating layer 23. Thereby, as mentioned later, when each ofthe organic layers 25 a, 25 b and 25 c generates light, the light is nottransmitted to outer side from the upper face or the side faces buttransmitted from its lower face to the transparent substrate 21 via thefirst electrode 22 which is a transparent electrode and is emittedfurther to the outer side.

In forming the optical element 2 having such a constitution, firstly, asshown by FIG. 2A, the transparent substrate 21 comprising glass isprepared. Successively, on the transparent substrate 21, a film of atransparent conductive material excellent in light transmittingperformance and having excellent conductivity or ITO in this embodimentis formed by a physical film forming process such as sputtering processand the first electrodes 22 in a stripe-like shape are formed as shownby FIG. 2B by using publicly-known lithography technology and etchingtechnology. Further, in respect of dimensions of the first electrodes22, according to the embodiment, the thickness is set to 200 nm and thewidth (w1) is set to 140 μm.

Next, in a state of covering the first electrodes 22, an insulatingmaterial or polyimide in this embodiment, is coated above thetransparent substrate 21 by a thickness of about 1 μm by the spincoating process, successively, the openings 24 are formed on the firstelectrodes 22 as shown by FIG. 2C by using publicly-known lithographytechnology to thereby provide the insulating layer 23. In this case, inrespect of the opening 24, according to the embodiment, a rectangularshape of 290 μm in length and 80 μm in width (width w2) is formed.

Further, polyimide is used for the insulating layer 23 since it hasexcellent insulating performance and excellent adhering performance inrespect with a matrix. However, other material may naturally be used sofar as it is an insulating material having such properties.

Next, as shown by FIG. 2D, the organic layers 25 a of red color (R) areformed in the openings 24 and on the insulating film 23 at surroundingsthereof by a vacuum vapor deposition process by using a vapor depositionmask arranged with a plurality of openings in a rectangular shape. Next,as shown by FIG. 2E, similar to formation of the organic layers 25 a,the organic layers 25 b of green color (G) and the organic layers 25 cof blue color (B) are successively formed.

Further, in forming the organic layers 25 a, 25 b and 25 c, vapordeposition is carried out by using vapor deposition masks incorrespondence with the respective colors by respectively interchangingthem or by moving the same vapor deposition mask. Accordingly, theprovided organic layers 25 a, 25 b and 25 c are formed to pile up in arectangular shape in plane view independent from each other. Accordingto the embodiment, there is provided a rectangular shape of 320 μm inlength and 110 μm in width (width w3). Therefore, the above-describedrelationship among the width w1 of the first electrodes 22, the width w2of the openings 24 and the width w3 of the organic layers 25 a, 25 b and25 c, that is, the relationship of w1 (=140 μm)≧w3(=110 μm)>w2(=80 μm)is satisfied.

Further, according to the embodiment, thicknesses of the organic layers25 a, 25 b and 25 c are constituted to differ from each other such thatthe thickness of the red organic layer 25 a is 150 nm, the thickness ofthe green organic layer 25 b is 100 nm and the thickness of the blueorganic layer 25 c is 200 nm.

Next, as shown by FIG. 2F, the second electrodes 26 in a stripe-likeshape are formed by the physical forming process of sputtering processor vapor deposition process or the like by using a vapor deposition maskhaving openings in a stripe-like shape to be substantially orthogonal tothe first electrodes 22 and in a state of covering the organic layers 25a, 25 b and 25 c as shown by FIG. 1A. According to the embodiment, thereare provided the second electrodes 26 made of aluminum in a stripe-likeshape having the thickness of 300 nm and the width of 440 μm.

Thereafter, an insulating layer (illustration is omitted) and so on areformed to cover the second electrodes 26 to thereby provide the opticalelement 20 of full color.

Further, as the method of forming the organic layers 25 a, 25 b and 25 cand the second electrodes 26, in place of the vapor deposition maskprocess, other patterning process, for example, a method of usinglithography technology and etching technology or the like may be used.

According to the optical element 20, the organic layers 25 a, 25 b and25 c are formed in an island-like shape independently from each other.Therefore, when the optical element 20 is driven by the simple matrixsystem, for example, as shown by FIG. 3, an organic EL display 30 isconstituted by connecting a brightness signal circuit 14 to the side ofthe first electrodes 22 and connecting the scanning circuit 23 to theside of the second electrodes 26.

When the organic EL display 30 is constituted in this way, and driven bythe simple matrix system by connecting the brightness signal circuit 14and the scanning circuit 13 to the respective electrodes, voltage dropin the first electrodes 22 which are transparent electrodes can bereduced by which voltage applied on the organic layers 25 a, 25 b and 25c constituting the respective pixels can be made substantially uniformand the light emitting brightness can be made uniform.

Further, power consumed in the first electrodes 22 can be madenegligibly small and accordingly, power consumption can be reduced.

Further, according to the above-described optical element 20, theorganic layers 25 a, 25 b and 25 c are formed in an island-like shapeindependently from each other. Therefore, arrangement of the organiclayers 25 a, 25 b and 25 c become arbitrary and therefore, thearrangement of the unit pixels constituted by the respective organiclayers 25 a, 25 b and 25 c can arbitrarily be constituted, therefore,the pixels in correspondence with respective colors of red color (R),green color (G) and blue color (B) can also be arranged in a delta shapeas shown by FIG. 4.

Further,-according to the above-described optical element 20, theorganic layers 25 a, 25 b and 25 c are formed in an island-like shapeindependently from each other and the upper face side, that is, upperfaces and side faces of the organic layers 25 a, 25 b and 25 c arecovered by the second electrodes 26. Accordingly, as shown by arrowmarks in FIG. 5, when the organic layer 25 b (25 a, 25 c) generateslight, the light is reflected without being transmitted to the outerside from the upper face or the side faces, as a result, almost all ofthe light is transmitted from the lower face of the organic layer to thetransparent substrate 21 via the first electrode 22 which is atransparent electrode and is emitted to the outer side.

Accordingly, light generated by the organic layers 25 a, 25 b and 25 ccan effectively be utilized by which there can be carried out a displayhaving higher brightness and more excellent color reproducingperformance. In this case, such an effect is achieved not only for colordisplay but similarly for monochromatic display.

Further, according to the above-described element 20, the insulatinglayer 23 having the openings 24 are provided between the firstelectrodes 22 and the organic layers 25 a, 25 b and 25 c and the opening24 are formed in a size smaller than the plane view shape of the organiclayers 25 a, 25 b and 25 c. Therefore, the organic layers 25 a, 25 b and25 c are not directly present particularly above the end portions 22 ain the width direction of the first electrodes 22 and the insulatinglayer 23 is interposed therebetween, accordingly, shortcircuit betweenthe first electrodes 22 and the second electrodes 26 directly formedthereabove is prevented and the pixels can firmly be selected.

Further, according to the above-described optical element 20, in a stateof plane view, the organic layers 25 a, 25 b and 25 c are arrangedwithin the width of the first electrodes 22 and accordingly, the widthw3 of the organic layers 25 a, 25 b and 25 c is made equal to or smallerthan the width w1 of the first electrodes 22 (w1≧w3). Therefore, indesigning, the width w1 of the first electrodes 22 can relatively beincreased by which a reduction in the wiring resistance of the firstelectrode can be achieved.

Further, although according to the above-described embodiment, thesecond electrodes 26 are formed in a stripe-like shape having the samewidth over an entire constitution, the present invention is not limitedthereto but, otherwise, for example, as shown by FIG. 6, there may beconstituted second electrodes 27 in a stripe-like shape in which thewidths are partially narrowed. However, also in this case, it ispreferable to constitute a plane view shape such that the upper facesides of the organic layers 25 a, 25 b and 25 c can be covered by thesecond electrodes 27.

Further, although according to the above-described embodiment, thesecond electrodes 26 are provided directly on the organic layers 25 a,25 b and 25 c, as shown by FIG. 7, metal films 28 having a sizesubstantially the same as the upper face shape of the organic layers 25a, 25 b and 25 c may be installed thereabove and the second electrodesmay be installed thereabove. Further, as shown by FIG. 8, metal films 29having a shape exactly covering the upper faces and side faces of theorganic layers 25 a, 25 b and 25 c may be installed thereon and thesecond electrodes 26 may be installed thereon.

Further, the metal films 28 or the metal films 29 may be made tofunction as the second electrodes. In this case, electrodes formed onthe metal films 28 or 29 constitute wirings for conducting electricityto the metal films 28 or 29. In respect of the wirings, the shape andthe dimensions are arbitrary and the wirings may naturally be madesmaller than the size of the organic layers 25 a, 25 b and 25 c.

Further, according to the invention, also in respect of the opening 24of the insulating layer and the organic laminated members 25 a, 25 b and25 c, the dimensions and shapes are not limited to those in theabove-described embodiments but are arbitrary. Naturally, in respect ofindividual ones of the openings 24 and the organic laminated members 25a, 25 b and 25 c, the sizes or shapes may be changed in accordance withforming positions or colors.

Further, although according to the above-described embodiments, anexplanation has been given of an example in the case in which theoptical element according to the invention is applied to a color organicEL display, the present invention is applicable also to a monochromaticorganic EL display and is further applicable not to the organic ELdisplay under the simple matrix drive system but an organic EL displayby an active matrix system driven by TFTs (thin film transistor) or thelike.

Further, the optical element according to the invention can also beutilized as a light source of a dial or the like and in that case, theoptical elements need not to arrange in a matrix-like shape. Further,the optical element is applicable also to a spontaneous light emittingelement for a filter adjusting chromaticity or optical communicationapparatus or the like and is further applicable to an image takingelement or the like as an application when incident light is convertedinto electric signal.

As has been explained above, according to the optical element of theinvention, a plurality of organic layers are provided in a state ofbeing independent from each other in an island-like shape andaccordingly, arrangement and combination of organic layers, cathodes andanodes can arbitrarily be carried out by which selection and arrangementof pixels comprising the organic EL elements and electrodes formingconstituent elements of the elements become arbitrary and accordingly,the second electrodes comprising a metal or an alloy having smallresistance can be used for electrodes on the scanning side where thelarger current flows.

Further, the organic layer is arranged within the width of the firstelectrode in the plane view state and accordingly, the width of thefirst electrode can be made relatively large in design by which thewiring resistance of the first electrode can be reduced and accordingly,a reduction in power consumption can be achieved.

Further, there is installed the insulating layer having the openings forcommunicating the first electrodes with the organic layers are installedbetween the first electrodes and the organic layers and the openings areformed in a size smaller than the plane view shape of the organic layersand accordingly, particularly, the organic layers are not presentdirectly above end portions in the width direction of the firstelectrodes but the insulating layer is interposed therebetween,therefore, shortcircuit between the first electrodes and the secondelectrodes directly formed thereabove is prevented and pixels can beselected firmly.

Further, the first electrodes and the second electrodes are formedrespectively in a stripe-like shape and are arranged substantiallyorthogonally to each other, the organic layers are provided at positionsintersecting with these in an island-like shape independently from eachother. Therefore, when the upper face sides of the organic layers areformed in a state of being covered by the second electrodes, lightgenerated at the organic layers are not guided to other ones of theorganic layers but can be taken out efficiently from the transparentsubstrate side as display light.

According to the organic EL display of the invention, the plurality oforganic layers are provided in a state of being independent from eachother in an island-like shape and accordingly, arrangement andcombination of the organic layers, the cathodes and the anodes canarbitrarily be carried out by which selection and arrangement of thepixels comprising the organic EL elements and electrodes constitutingthe constituent elements of the elements can arbitrarily be carried outand therefore, there can be constituted the second electrodes made of ametal or an alloy having small resistance by electrodes on the scanningcircuit side where the larger current flows.

Further, large current can be prevented from flowing in the firstelectrodes comprising a transparent conductive material having largeresistance by such a constitution by which nonuniformity of lightgeneration of respective pixels caused by voltage drop can be minimizedand accordingly, deterioration in the display function can be prevented.

Further, large current is not flowed in the first electrodes havinglarge resistance and therefore, power consumed there is reduced andaccordingly, low power consumption can be achieved.

Further, the plurality of organic layers are provided in a state ofbeing independent from each other in an island-like shape by whicharrangement and combination of the organic layers, the cathodes and theanodes can arbitrarily be carried out and accordingly, for example, in acolor organic EL display, pixels respectively in correspondence with red(R), green (G) and blue (B) can arbitrarily be arranged and accordingly,for example, a delta arrangement can also be constituted.

Further, the first electrodes and the second electrodes can be formedrespectively in a stripe-like shape and are arranged substantiallyorthogonally to each other and organic layers are provided independentlyfrom each other in an island-like shape at positions intersecting withthese and accordingly, when the upper face sides of the organic layersare formed in a state of being covered by the second electrodes, lightgenerated at the organic layers is not guided to other ones of theorganic layers but can efficiently be taken out from the side of thetransparent substrate as display light.

Further, light generated in the organic layers can efficiently be takenout as display light in this way and accordingly, drive voltage or drivecurrent can be reduced by which a display having higher brightness,longer life and lower power consumption and higher reliability can berealized.

Further, light generated in the organic layer does not reach other pixelby being guided in the organic layer and accordingly, deterioration ofcolor reproduction caused by cross talk can be prevented andaccordingly, there can be realized a display having high functionexcellent in color reproducing performance.

What is claimed is:
 1. An optical element comprising: a plurality offist electrodes formed on a substrate; a plurality of organic layers atleast including organic light emitting materials formed on the pluralityof first electrodes; a plurality of second electrodes formed on theplurality of organic layers; the plurality of first electrodes and theplurality of second electrodes being formed to be substantiallyorthogonal to each other; the plurality of organic layers being formedin an island-like shape at positions at which the plurality of firstelectrodes and the plurality of second electrodes intersect with eachother, wherein a resistance value of the plurality of first electrodesis different than a resistance value of the plurality of secondelectrodes; a signal circuit connected to said plurality of firstelectrodes; and a scanning circuit connected to said plurality of secondelectrodes, wherein each of said first electrodes has a relativelylarger resistance value and each of said second electrodes has arelatively smaller resistance value.
 2. An optical element as claimed inclaim 1, wherein the second electrodes are formed to cover upper facesand side faces of the organic layers.
 3. An optical element as claimedin claim 1, wherein the first electrodes are formed to extend in onedirection, the second electrodes are formed to extend to other directionand when a width of the first electrodes in a direction orthogonal tothe one direction is designated by a notation w1, a width of theopenings in a direction orthogonal to the one direction is designated bya notation w2 and a width of the organic layers in a directionorthogonal to the one direction is designated by a notation w3, thefollowing relationship is established, w1≧w3≧w2.
 4. An optical elementas claimed in claim 1, wherein the first electrodes comprise ITO (indiumtin oxide) and the second electrodes comprise Al (aluminum).
 5. Anoptical element as claimed in claim 1, further comprising: thirdelectrodes disposed between the organic layers and the secondelectrodes; and wherein the third electrodes are formed to cover upperfaces and side faces of the organic layers.
 6. An optical element asclaimed in 1, wherein the insulating layer is made of polyimide.
 7. Anoptical element as claimed in claim 1, wherein the openings are formedin a rectangular shape.
 8. An optical element as claimed in claim 1,wherein the organic layers include organic layers of red color, greencolor and blue color.